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Tue, 6 Mar 2018 18:21:51 +0000 From: Dexuan Cui To: "bhelgaas@google.com" , "linux-pci@vger.kernel.org" , KY Srinivasan , Stephen Hemminger , "olaf@aepfle.de" , "apw@canonical.com" , "jasowang@redhat.com" CC: "linux-kernel@vger.kernel.org" , "driverdev-devel@linuxdriverproject.org" , Haiyang Zhang , "vkuznets@redhat.com" , "marcelo.cerri@canonical.com" , "Michael Kelley (EOSG)" , Dexuan Cui , Jack Morgenstein , "stable@vger.kernel.org" Subject: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items Thread-Topic: [PATCH v3 3/6] PCI: hv: serialize the present/eject work items Thread-Index: AQHTtXf/Svimyxa0lEG1rzwqwCqgUQ== Date: Tue, 6 Mar 2018 18:21:51 +0000 Message-ID: <20180306182128.23281-4-decui@microsoft.com> References: <20180306182128.23281-1-decui@microsoft.com> In-Reply-To: <20180306182128.23281-1-decui@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: git-send-email 2.15.1 authentication-results: spf=none (sender IP is ) smtp.mailfrom=decui@microsoft.com; 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DIR:OUT; SFP:1102; SCL:1; SRVR:KL1P15301MB0021; H:KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM; FPR:; SPF:None; PTR:InfoNoRecords; A:1; MX:1; LANG:en; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-microsoft-antispam-message-info: BnTYXDTiNR7cIV22RE6DCNgaDWrNiI6dDiaqV+LAoM6bzCDxk4kpAgAudEmJlQFv6xICAbt8vWumiwgYANtPmWR0TwDzoC1HaWVr5WzZfeZegxgsQSp+2cHrtUmH0Uc8nJEErwmF+yP6LVr5r9+Zfme5VTjqpZKSnR5g764Huhx6/pvGWbVG3bcus9kpnoW4BAIr4q+TKu0Db+9K51m3pm/aqdmIQlZH9WROlr086ibnChFnCnpK/EWGYu7wlMYQvVQcG3SNszcXPRupqIp99qIUbw814n6+hpblYT3a7bqbGkXneaMNzZb6IQyJ89N7q0yqUqiw+5lTo1z+vbCJMQ== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1a32b673-c0e8-4301-360a-08d5838f2215 X-MS-Exchange-CrossTenant-originalarrivaltime: 06 Mar 2018 18:21:51.3846 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: KL1P15301MB0021 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When we hot-remove the device, we first receive a PCI_EJECT message and then receive a PCI_BUS_RELATIONS message with bus_rel->device_count == 0. The first message is offloaded to hv_eject_device_work(), and the second is offloaded to pci_devices_present_work(). Both the paths can be running list_del(&hpdev->list_entry), causing general protection fault, because system_wq can run them concurrently. The patch eliminates the race condition. Signed-off-by: Dexuan Cui Tested-by: Adrian Suhov Tested-by: Chris Valean Cc: Vitaly Kuznetsov Cc: Jack Morgenstein Cc: stable@vger.kernel.org Cc: Stephen Hemminger Cc: K. Y. Srinivasan Reviewed-by: Michael Kelley Acked-by: Haiyang Zhang --- drivers/pci/host/pci-hyperv.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 04edb24c92ee..aaee41faf55f 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -461,6 +461,8 @@ struct hv_pcibus_device { struct retarget_msi_interrupt retarget_msi_interrupt_params; spinlock_t retarget_msi_interrupt_lock; + + struct workqueue_struct *wq; }; /* @@ -1770,7 +1772,7 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus, spin_unlock_irqrestore(&hbus->device_list_lock, flags); get_hvpcibus(hbus); - schedule_work(&dr_wrk->wrk); + queue_work(hbus->wq, &dr_wrk->wrk); } /** @@ -1845,7 +1847,7 @@ static void hv_pci_eject_device(struct hv_pci_dev *hpdev) get_pcichild(hpdev, hv_pcidev_ref_pnp); INIT_WORK(&hpdev->wrk, hv_eject_device_work); get_hvpcibus(hpdev->hbus); - schedule_work(&hpdev->wrk); + queue_work(hpdev->hbus->wq, &hpdev->wrk); } /** @@ -2460,11 +2462,17 @@ static int hv_pci_probe(struct hv_device *hdev, spin_lock_init(&hbus->retarget_msi_interrupt_lock); sema_init(&hbus->enum_sem, 1); init_completion(&hbus->remove_event); + hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0, + hbus->sysdata.domain); + if (!hbus->wq) { + ret = -ENOMEM; + goto free_bus; + } ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0, hv_pci_onchannelcallback, hbus); if (ret) - goto free_bus; + goto destroy_wq; hv_set_drvdata(hdev, hbus); @@ -2533,6 +2541,8 @@ static int hv_pci_probe(struct hv_device *hdev, hv_free_config_window(hbus); close: vmbus_close(hdev->channel); +destroy_wq: + destroy_workqueue(hbus->wq); free_bus: free_page((unsigned long)hbus); return ret; @@ -2612,6 +2622,7 @@ static int hv_pci_remove(struct hv_device *hdev) irq_domain_free_fwnode(hbus->sysdata.fwnode); put_hvpcibus(hbus); wait_for_completion(&hbus->remove_event); + destroy_workqueue(hbus->wq); free_page((unsigned long)hbus); return 0; }